The present invention concerns a process for obtaining a plate of variable transparence and the product thereof. More particularly, the inventor is concerned with a plate whose transparence at every point is a function of the coordinates of this point.
Specifically, the invention proposes a process for manufacturing such plates in large quantities and in a relatively inexpensive manner. The process is such that a plurality of different plates are obtainable which are strictly identical with one another.
For this purpose, a three-dimensional form representative of the function is made. This form has a base of a contour homothetic of that of and transparent surface to be obtained. The thicknesses measured from the base is proportional to the values of the function, and the form is carried out or executed in a material which absorbs X-rays. Then, a radiograph of this three-dimensional form is made on the desired scale, and the transparent plate is the support of the radiograph thus obtained.